Method of receiving telegraph-signals



c. H. TEEGARDEN. METHOD OF RECEIVING TELEGRAPH SIGNALS.

APPLICATION FlLED SEPTL9' I918.

Patented July 13, 1920.

Jove/afar C far/Y. Tbe ardefl M W h ,y

UNITED STATES CIEL'ES'IER H. TEEGARDEN, OF WASHINGTON, DISTRICT OF COLUMBIA.

METHOD OF RECEIVING TELEGRAPH-SIGNALS.

Specification of Letters Patent.

Patented Jaime, 1920.

Application filed September 9, 1918. Serial No. 253,308.

To all whom it may concern:

Be it known that T, Crrns'rnn H. Tnnmrnunn, a citizen of the United States, residing at Vashington, in the District of G0- .lrunbia, have invented certain new and useful Improvements in Methods of Receiving Tclegrapix-Signals, of which the following is a specification.

hfly invention relates to telegraphy and more particularly to a means for receiving messages sent over the simplex or one way Morse telegraph. Very often it is found desirable to attach a temporary supplementary station to such a telegraph line for the purpose of permitting the receiving of all messages transmitted over the line at such supple]uentary station. hiy invention aims to provide such a supplementary station which may be attached to the simplex Morse line and will then receive all messages over the line without in any way disturbing the line.

In the drawings the single figure represents two stations oi? a closed circuit telegraph line showing my invention attached thereto.

Referring to the drawings for a complete description of my invention there are shown two stations, A and B, which are in all respects identical. Accordingly a description of one will suffice to describe both.

The station A is provided with a relay 1 connected to battery 2 through telegraph key This telegraph key is normally shunted by switch t. a The other side of battcry 2 is connected to ground at 5, and the other side of relay 1 is connected to the line 6. The relay 1 is provided with an arrnaturc 7 nornuilly retracted by spring 8 against a stop 10. Upon energization of the relay 1 the armature 7 'is attracted to engage the contact 9.. This contact 9 is connected to one terminal oi the sounder 11, the other terminal oi which is connected to one terminal of battery 12. The other terminal of this battery 12 is connected to the armature 7 The sounder 1.1 is provided with the usual armature 15 which is normally held retracted by a spring 13 against a stop 14.

The operation of the above described apparatus is as followsz Normally a current flows from battery 2 at station B through switch 1, relay 1, line 6 relay 1 of station A, switch l, battery 2 to ground at 5 of statlon A, and thence back; to battery 2 of station B through the ground 5 at that station. The relays 1 are normally energized by this current to hold armatures 7 in their raised position a ainst the contacts 9. When it is desired to send a message from either sta tion, the switch t at that station is opened to discontinue the current in the relays 1 and permit the armatures 7 to be retracted by the springs 8 and thus terminates the energization of the sounders 11. The key 3 in shunt to the open switch a is then depressed by the operator, and. at eachdepression a current flows through the line 6 to energize the relays 1, attract the armatures 7, and

' thus energize the sounders 11 to indicate the beginning of a signal, while at each release of the key 3 the relays 1 are deenergized to release armature and thus deenergize the Sounders 11 to indicate the termination of the signal. The above operation is the usual simplex telegraph line and is well known in the art.

In the system which I have illustrated, the battery is divided between the two sta tions, as shown. From this it follows that some point between these batteries is of the same potential as the ground, the location of the point depending on the relative battery voltages and on the resistances of the various parts. The point 37 may or may not be this point, but, in any event, the point 37 is normally at a definite potential from ground. When, however, either station opens itsswitch 1, the point 37 will no longer be at the same potential from ground and the change in potential will. cause a current to flow tl'n'ough a circuit, including a condenser, and connected from this point to ground. My inventionmalres use of this principle.

My invention consists in a wire 16 connected to the line 6 at any desired point 87 through the variable condenser 32 and the variable resistance 38. The other end of this wire 16. is connected to the armatures 19 and 20 of the two polarized relays 17 and 18. The armature 19 normally engages a contact 21 which is connected to one terminal of the relay 18, the other terminal of which is connected to the ground at 27. The armature 20 normally engages a contact 22 which is connected to one terminal of the relay 17, the other terminal of which is connected to ground at 28. The relays 17 and 18 are provided with. supplemental contacts 25 and 26 nected to one terminal'of battery '23, the

other terminal of which is connected to the sounder 24. The other terminal of this sounder is connected to the wire 16. The sounder 24 is provided with .an armature 29 normally retracted by a spring 80 against a stop-31. p

The operation of my attachment or supple'mentary receiving set is as follows \Vithboth switches 4 in their closed position the potential of the point 87 is at a constant diflerence from that of the grounds 2? and 28 andno current will flow through relays 17 and .18. Whenever either switch 4, for example that at station A, is open, the polarity or the point 37 will be increased or decreased with respect to that of the grounds 2,7 and 28. In the present case the potential of the point 37 will increase and accordingly a momentary current will flow from the such direction as to tend to move .the arma-' ture 19 against the contact 21 with which it is already in engagement. 'Accordingly the armature 19 will not move from its position against the contact 21. In flowing through relay 18 the current will traverse the coil in such direction as to move the armature 20 against the contact 26. This will close a circuitthrough sounder 24 as follows from battery 23 to contact 26, armature 20, line 16, sounder 24, and back to battery 23. This current will attract the armature 29 and indicate the opening of the circuit through line 6. Due to the interposition of the condenser 32 in conductor 16, the current energizing the relay 18 will be but momentary. The relays 17 and 18 are so constructed, however, that their armatures'will remain in either extreme position. Accordingly until another impulse comes from conductor 16, the armature 20 will remain in engagement with contact 26 and armature 29 will remain attracted. Nhen,

however, the key 3 at station A is depressed,

current will againfiow through line 6v and relays land the point 37 will return to its the point 37 thence to the ground 5 through the two stations in parallel, and thence back.

quent releases of key 3 will cause attractions to the condenser through the ground 27,

relay 18 and conductor 16. No current can flow, due to this impulse, through the coil of relay 17 since the armature .20 is out of engagement with the contact 22. Accordingly this impulse can have no effect on armature 19. This impulse, however as has been stated, does fiow through relay 18 and flows through the coil thereof in such direction as to return the armature 20 to its normal position against contact 22, and thus open the circuit of sounder 24 to release armature 29 and indicate the termination ot' the open circuit condition of line 6. Subse- 39 of armature 29 and subsequent depressions of key 3 will cause corresponding retractions of armature 29, each retraction of armature 29 indicating the beginning ofthe transmission of a signal and each attraction of the armature indicating the termination of such signal, the first attraction indicating the opening of theline switch 4 and the final retraction indicating the reclo sing of the switch 4. The opening and closing of the switch 4 as thus indicated will indicate-the commencement and conclusion of an entire message. v

' It will be apparent'from the above that my supplementary receiving set will receive any message sent from station A to station B by means of the relay 18 through its control'of the sounder 24. It will be apparent from the diagram shown in the drawings and from the above descriptiointhat the relay 1'? will functionsimilarly to control the sounder 24 to receive any message sent from station 13' to station A. It will also be apparent that inspection of the relays 17 and 18 will indicatewhich station is sending the message being received by the sounder 24.

It will be apparent that where metallic return is employed, the terminals of the relays 17 and 18 will be connected to this metallic return instead of to ground at 27 and 28, and that this change will in nowise affect the operation of my receiving set. It will also be apparent that my set wil'lfoperate equally well upon alineemploying normally open circuit since the fundamental principle of my invention depends on the change in line potential and this is iurnished by the usual open circuit systems as well as by the closed-circuit system 'd escribed; Further, my supplementary set is not affected in its ultimate result when all the line battery isplaced at one station. In such a case, whilethere will normally be a greater difference in potentialbetween points 37 and the grounds 27' and28, the normally existing potential would still be an intermediate potential, since this potential would still beincreased by the opening of the I switch 4 at one end and decreased by the opening of the switch 4 at the other end,

and accordingly opening of the circuit at one station will still cause an impulse to flow through my set in one direction while opening the circuit at the other station will cause an impulse to flow in the other direction.

From the above it will be apparent that my supplementary receiving set will operate to receive all messages transmitted over a simplex telegraph line irrespective of the position of the line battery and regardless of whether the circuit is normally closed or normally open. Further it will be apparent that since the fundamental principle of my invention is the utilization of the change of line potential, my supplementary receiving set will operate on any simplex telegraph line where such change in potential occurs.

In the above description I have used the term. simplementary receiving set to indicate a receiving set which is attached to an already existing complete telegraph line without disturbance of the line, to receive messages sent over the line. 1 have used the term simplex as indicatinga line from which but one message is transmitted at any one time. I have used the term sounder in a generic sense as indicating any device which will indicate or receive telegraph signals. a

While I have here set forth the preferred embodiment of my invention, the modifications herein suggested are considered to be within the scope of my invention, and I also consider as within the scope of my invention all. modifications which fall within the scope of the appended claims.

What I claim is l. A supplementary receiving set for a simplex telegraph line, comprising two relays, two sets of normally engaged contacts, one operated by each of said relays, a connection from the line to the coil. of each relay through the normally closed contacts of the other relay, respectively, a connection to ground from the other terminal of each coil, two sets of normally open contacts, one operated by each of said relays, connections whereby said normally open contacts are connected in parallel and a sounder circuit connected in series with said parallel con nected normally open contacts.

2. supplementary receiving set for a simplex telegraph line, comprising two relays, two sets of normally engaged contacts, one operated by each of said relays, a connection from the line to the coil of each relay through the normally closed contacts of the other relay, respectively, a connection to ground from the other terminal of each coil, two sets of normally open contacts, one operated by each of said relays, and a sounder circuit controlled by said normally open contacts.

3. A supplementary receiving set for a simplex telegraph line, comprising two relays, each relay being connected across the line, two sets of contacts, one set controlled by each relay, each set of contacts being interposed in the circuit of the other relay, respectively, two further sets of contacts, one set being controlled by each relay, and a sounder circuit controlled by said two further sets of contacts.

i. A supplementary receiving set for a simplex telegraph line, comprising two relays, each relay being responsive to change in line potential, two sets of contacts, one controlled by each relay, connections whereby each set controls the energization of the other relay, respectively, two further sets of contacts, one set being controlled by each relay, and a sounder circuit controlled by said two further sets of contacts.

A supplementary receiving set for a simplex telegraph line, comprising two relays, each relay being responsive to change in line potential, means controlled by each relay for controlling the cnergization of the other relay, two sets of contacts, one set'controlled by each relay, and a sounder circuit controlled by said two sets of contacts.

6. A supplementary receiving set for a simplex telegraph line, comprising two relays, each responsive to line conditions, two sets of contacts, one set controlled by each relay and controlling the energization of the other relay,respectively, two further sets of contacts, one set being controlled by each relay, and a sounder circuit controlled by said two further sets of contacts.

- 7. The combination with a simplex telegraph system comprising a line extending from one station to another station, of a supplementary receiving set comprising two relays, each responsive to line conditions two sets of contacts, one set controlled by each relay and controlling the energization of the other relay, respectively, and means directly connecting saidv supplementary receiving set with said line.

8. The combination with a simplex telegraph system comprising a line extending from one station to another station, of a supplementary receiving set comprising two relays, each responsive to change in line potential, means controlled by said relays to indicate the message being transmitted, means controlled by said relays to indicate the direction in which said message is being transmitted, and means directly connecting said supplementary receiving set with said line.

9. The combination with a simplex telegraph system comprising a line extending from one station to another station, of a supplementary receiving set comprising two relays, each responsive to line potential, two sets of contacts, one set controlled by each relay and controlling the energization of the other relay, respectively,and means directly connecting said supplementary receiving set with said line.

lOaThe combination with a simplex telegraph system comprising a line extending from one station to another station, of a supplementary receiving set comprising means responsive to change in line potential for indicating a message transmitted in one direction, means responsive to change in line potential for indicating a, message trans-- mitted in the otherdirection, and means c irectly connecting said supplementary receiving set with said line.

11. The combination with a simplex telegraph system comprising a line extending from one station to another station, of a supplementary receiving set comprising means responsive to line condition for indicating a message transmitted in one direction, means responsive to line conditions for indicating a message transmitted in the other direction, intermediate means controlled by each responsive means for controlling the other responsive means, respectively, and means directly connecting said supplementary receiving set with'said lme;

12. The combination with a simplex telegraph system comprising a line extending from one station to another station, of a supplementary: receiving set comprising means for indicating the message being transmitted, means responsive to line potential for controlling said indict ting means directly connecting said supplementary receiving set with said line.

13. The combination With simplex telew graph system comprising a line extending from one station to'another station, of a supplementary receiving .set comprising means responsive to line potential for. indicating a messagebeing transmitted in one direction, means responsive to line potential for indicating a message being transmitted in the other direction, intermediate means controlled by each or" said responsive means to control the other responsive means, re spectively, and means directly connecting said supplementary receivingset with said line. V

14., The combination with a simplex telegraph system comprising a line extending from one station to another station, of a supplementary receiving set comprising means for indicating a message being trans mitted over said'line, two separate means,

eachv responsive to change in line potential,

crmsrnii H. TEEGARDEN. 

